There is known a portable storage unit which allows the user to exchange not only the storage medium but also the entire storage device. For example, Japanese Patent Laid-Open No. 8-167273 discloses a card type disk unit complying with PCMCIA standards. On Mar. 6, 2002, iVDR Hard Disk Drive Consortium (http://www.ivdr.org) has released a portable storage unit based on a 2.5″ hard disk unit (“iVDR” is a trademark of iVDR Hard Disk Drive Consortium).
When the whole storage device is exchanged instead of just the storage medium, since the storage device does not have any eject mechanism, an eject mechanism must be arranged outside to eject it. For example, Japanese Patent Laid-Open No. 10-301719 discloses in FIG. 3 an arrangement in which a disk drive is ejected by driving an eject mechanism on the basis of a control signal output from a drive controller. Japanese Patent Laid-Open No. 2000-276258 discloses in FIG. 1 an arrangement in which a dummy IDE device detects depression of an eject switch, and an eject mechanism is driven on the basis of a control signal output from the dummy IDE device to eject a docked IDE device.
In a portable storage unit such as a CD-ROM drive or MO drive in which only a storage medium is replaced, the storage medium can be ejected by operating an eject button or the like, or an eject command exchanged via an interface such as ATA or SCSI which connects the portable storage unit and a host apparatus such as a personal computer.
In the above references, a control signal for driving the eject mechanism is output from a block different from a disk drive (IDE drive). The block is not connected to an interface signal such as ATA or SCSI, or even if the block is connected, it does not receive any eject command. Eject by an eject command is not executed.
Considering the versatility of the unit, it is desirable to connect a portable storage unit including a storage device and eject mechanism and a host apparatus by a single interface signal such as ATA or SCSI. In the above references, only the storage device is connected by an interface signal such as ATA or SCSI, and connected by a signal line different from that of the eject mechanism.
In the above references, the storage device such as a disk drive and the eject mechanism are separately controlled. That is, even while the storage device performs storage operation, it can be ejected. If eject operation is executed at an improper timing, data to be stored is lost without being stored, and in the worst case, the unit is damaged. The host apparatus may monitor operation to the storage device, and allow eject only when no operation (particularly write operation) is done. Almost all recent storage devices such as a disk drive are equipped with write cache memories. Even if the host apparatus determines that write operation has ended, write of data in the cache memory may actually be in progress, failing to cope with all situations.
Accordingly, it is desired to overcome the conventional drawbacks. Especially, it is desired to allow ejecting a mounted storage unit by an eject command via an interface which connects an information processing apparatus and the detachable storage unit.
Also, it is desired that the above information processing apparatus and storage unit are connectable by a single interface.
Also, it is desired that the storage unit is always safely ejected from the information processing apparatus regardless of the eject instruction timing.